Animal well-being and treatment are major concerns for animal welfare groups and animal agriculturalists. Animal well-being and treatment are continual concerns because stressed or uncomfortable animals do not efficiently and profitably produce milk, meat, or eggs.
Implant technology, that is to say, procedures involving subcutaneous implant of pharmaceuticals and medical devices, is now well accepted and widespread in the areas of animal health and production enhancement as well as human health. Growth stimulants are commonly used to enhance the body weight of animals which are raised for harvesting, such as cattle, swine, sheep, turkeys, chickens, and the like.
In the case of cattle and sheep, approved growth stimulants are administered as solid pellets which are injected by an implanter equipped with a hypodermic needle. The needle is used to make a surface self-sealing and, non-coring implant receiving puncture beneath the skin of the ear of the animal. Small pellets of growth-promoting hormones are forced through the needle and left under the skin as the needle is removed from the ear. The ears are commonly discarded in harvesting, such that no unabsorbed residues of such pellets will end up in food products intended for humans or domestic animals. The pharmaceutical in the pellets is normally formulated for timed release and continuous, sustained absorption of the active ingredients over an extended period of time.
Many types of pharmaceuticals such as bioactive compounds may also be implanted and include insulin, endocrine hormones for control of reproduction, vaccines, and biocides for flea and parasite control in humans, horses, and domestic animals such as dogs and cats. The compounds may be administered subcutaneously at any suitable location on the body. Included as such a pharmaceutical are synthetic derivatives of naturally occurring compounds such as trenbolone acetate, a synthetic derivative of testosterone currently used in cattle growth-promoting implants. As those skilled in the art will appreciate, similar therapeutic procedures may be employed to implant drug delivery devices such as controlled release osmotic pumps in humans and animals as well as transponder devices in animals.
In the case of food-producing animals, the pellets are normally implanted while an animal is confined in a chute. An ear is grasped in one hand, and an implanter device having a large hypodermic needle is used to puncture the hide and subcutaneously inject a pellet dose into an implant-receiving puncture. The implanting must be done carefully to insure that the pellets are properly placed and that no pellet remains extending from the puncture outside the hide. The procedure must be carried out quickly since the animals are not entirely cooperative and may shake their heads to free the held ear.
In addition to implanting pharmaceutical pellets, is it also known in the art to implant certain anti-inflammatory agents. As those skilled in the art will appreciate, when tissue injury occurs, whether caused by bacteria, trauma, chemicals, heat, or any other phenomenon, the body's inflammatory response is stimulated. In response to signals released from the damaged cells (e.g., cytokines), extravascularization of immune effector cells is induced. Under ordinary circumstances these invading immune effector cells kill the infectious agent and/or infected or damaged cells (through the release of killing substances such as superoxides, performs, and other antimicrobial agents stored in granules), remove the dead tissues and organisms (through phagocytosis), release various biological response modifiers that promote rapid healing and covering of the wound (quite often resulting in the formation of fibrotic scar tissue), and then, after the area is successfully healed, exit from the site of the initial insult.
Once the site is perceived to be normal, the local release of inflammatory cytokines ceases and the display of adhesion molecules on the vessel endothelium returns to basal levels. In some cases, however, the zeal of these interacting signals and cellular systems, which are designed to capture and contain very rapidly multiplying infectious agents, act to the detriment of the body, killing additional, otherwise healthy, surrounding tissue. This additional unnecessary tissue death further compromises organ function and sometimes results in death of the individual.
The present invention provides a pain relief pellet system which delivers localized, controlled and sustained release of a predetermined quantity of one or more pain relief agents, in optional combination with one or more anti-inflammatory agents, one or more polymeric excipients, and/or one or more surfactants. Applicants' anesthetic/analgesic pellet system can be used in combination with one or more pharmaceutical implants as part of a single procedure in order to provide desired pharmaceutical to the animal while simultaneously alleviating pain and, optionally, inflammation at the injection site.